Video extensometer and marker line positioning method based on video extensometer

Abstract

The invention discloses a video extensometer and a marker line positioning method based on the video extensometer. The method comprises the steps of 1, arranging a first coding area and a first marking area at the upper end of a test piece to be tensioned by the video extensometer in sequence, and arranging a second coding area and a second marking area at the lower end of the test piece in sequence, wherein preset coding images are stuck to the interior of the first coding area and the second coding area, and preset marking images are stuck to the interior of the first marking area and the second marking area; 2, transmitting a test piece image which is acquired by an image acquiring device and contains the first coding area, the first marking area, the second coding area and the second marking area to a central processor, and searching for and acquiring the width of the first coding area and the width of the second coding area according to the geometrical characteristics of the preset coding images; 3, extracting the preset marking images within the range of the first marking area and the range of the second marking area, and determining the positions of marker lines corresponding to the preset marking areas in the first marking area and the second marking area through Hough transformation.

Description

technical field [0001] The invention relates to the field of marking line positioning, in particular to a video extensometer and a marking line positioning method based on the video extensometer. Background technique [0002] Because the traditional mechanical extensometer is subject to many restrictions in actual use, for example: in order to prevent damage to the knife edge, it must be removed before the specimen breaks, so the entire process cannot be measured, which affects the accuracy of the measurement; for softer The weight of the extensometer itself will cause the deformation of the test piece and cause errors in the measurement; for smaller materials such as particles, it cannot be clamped; for materials with large deformation, it will exceed its measurement range etc.; while the video extensometer solves these problems and makes the market demand for it more and more. [0003] Although the video extensometer researched abroad has reached a relatively high level, ...

AI Technical Summary

Problems solved by technology

[0002] Because the traditional mechanical extensometer is subject to many restrictions in actual use, for example: in order to prevent damage to the knife edge, it must be removed before the specimen breaks, so the entire process cannot be measured, which affects the accuracy of the measurement; for softer The weight of the extensometer itself will cause the deformation of the test piece and cause errors in the measurement; for smaller materials such as particles, it cannot be clamped; for materials with large deformation, it will exceed its measurement range and so on; and the video extensometer solves these problems, making the market demand for it is increasing

[0003] Although the video extensometer researched abroad has reached a high level, but the price is expensive, which greatly promotes the research of domestic video extensometer, but the level is generally low

Because the marking lines of the existing video extensometers are mostly fixed on both ends of the specimen with toothpicks, or the method of depicting the word "king" or a straight line is used; and the rough positioning of the upper and lower marking lines is not carried out, so that the search range is wide and the time is long; These factors have greatly affected the speed and accuracy of the video extensometer

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